KR20030020275A - Alternator for a motor vehicle with energising information output - Google Patents

Abstract

The automotive alternator includes an energy application regulating circuit, which itself is a breaker (Tex) controlled in series with the excitation coil, a freewheel component (DL) connected to the coil terminal, and an excitation state (Iexc) of the alternator. Circuits 10, 20, 30 for providing information Is1, Is2 on the substrate. According to the invention, the circuit generates means 10 for generating a first signal U1 which is proportional to the current Iex flowing in the breaker while the breaker is in the closed state and a second signal U2. As means 20, generate a second signal from the first signal while the breaker is closed and generate a second signal by storing (CD) the first signal that existed before the breaker was switched off while the breaker was open. Means 20 for making it.

Description

Automotive alternator, regulator circuit and monolithic circuit {ALTERNATOR FOR A MOTOR VEHICLE WITH ENERGISING INFORMATION OUTPUT}

Currently, it is common to have an automotive thermal engine with an electronic engine monitoring device for continuously adjusting the supply of the engine as a function of various measurement conditions and / or an electronic device for supervising the activation and deactivation of the electrical load of the vehicle. The electronic device is adapted to keep the load of the alternator below the maximum level.

One of these conditions is the degree of excitation of the alternator or alternator / starter of the motor vehicle, which itself represents the braking torque applied to the heat engine by the alternator or alternator / starter. Thus, when these measurements reflect a high resistance torque that is likely to stop the engine, the engine monitoring device may increase the supply mixture of the engine in order to avoid maintaining a sufficient idle speed and to avoid the aforementioned shutdown. do. Alternatively, the instrument consuming electricity from the on-board network of the vehicle can be disconnected momentarily.

In general, the degree of excitation of an alternator is given by the profile of an excitation control signal (typically, a pulse width modulation (PWM) signal) applied to a power semiconductor that, in combination with a freewheel diode, determines the current of the excitation winding.

There is a method of providing such a signal directly to the engine monitoring device in analog form or as a digital value representing the value. In particular, in the engine monitoring apparatus, an output signal generally known as "FR" for "field response" or "DF" for "digital field" is known. Applicant's document FR-A-2 695 269, in particular, discloses a device for generating a "FR" signal.

However, all devices that generate a signal based on an excitation control signal are sensitive to inherent variations in the effective excitation current as a function of temperature. More specifically, the ohmic resistance of the excitation winding is quite variable as a function of temperature and approximately 70% of this resistance when the temperature of the winding changes from 250 ° C. (cooling operation) to 200 ° C. (size during heating operation). Variation is generally observed.

This variation in resistance significantly changes the actual excitation current Iexc for any given excitation control signal. In a similar manner, a specific current corresponds to a very different profile of the excitation control signal and, depending on whether low or high temperatures are involved, correspond to a very different profile of the corresponding FR or DF signal.

Of course, the image of the effective current of the excitation winding can be obtained by using a shunt in series with the winding and by measuring the voltage across the terminals of this shunt. However, on the one hand, there is a significant problem of expressing the measured value since the ohm value of the shunt is quite variable with temperature, and on the other hand, there is a problem of heat dissipation that prevents the shunt from being made monolithic. .

Object of the present invention

The object of the present invention is the actual current flowing in the excitation winding of an alternator using means suitable for monolithic integration, in particular using excitation regulators and in a reliable and stable manner as a function of temperature. It is to generate a signal indicating.

To this end, the present invention according to the first aspect provides an alternator for automobiles, and the alternator for automobiles is a circuit for adjusting the current flowing in the excitation winding of the alternator, so as to be in on mode or off mode. A regulator circuit including a controlled controlled switch in series with the excitation winding, a unidirectional conducting freewheel component connected to a terminal of the excitation winding, and a circuit for delivering on the output information indicative of the excitation state of the alternator, The circuit for transmitting information indicating the excited state of the alternator,

Means for generating a first signal proportional to the current flowing in the control switch while the control switch is in an on state;

Means for generating a second signal, the second signal being generated based on the first signal while the control switch is in the on state, and present before the control switch is turned off while the control switch is in the off state. Means for generating a second signal by storing the first signal,

The current measuring circuit is characterized in that it comprises means for maintaining three terminals (source, drain and gate) of the excitation and measuring transistors at the same respective potentials.

It is to be understood that the term "AC alternator" in the foregoing specification not only means the alternator itself, but also means an alternator capable of operating as a motor, such as an alternator / starter.

Preferably, but not limited to, the alternator according to the present invention is as follows.

Means for generating a first signal comprises a current-mirror comprising a first semiconductor switch and a second semiconductor switch constituting said control switch.

The first and second semiconductor switches comprise first and second transistors composed of identical component cells.

The second transistor comprises a number of component cells equal to the fractional fraction of the number of component cells of the first transistor.

Means for generating a first signal comprises means for converting a current flowing in the second semiconductor switch into a voltage constituting the first signal.

Means for generating a second signal comprises means for generating digital information indicative of the first signal while the control switch is in an on state, and selectively storing the digital value from the moment when the control switch is turned off. Means;

Means for selectively storing the digital value comprises an increase / decrease circuit which receives on the input a turn off signal which is set based on the current in the control switch being zero.

Means for generating a second signal comprises a comparator receiving a first signal on a first input and receiving an analog signal obtained by the conversion of the digital information on a second input, the output of which is in increasing / decreasing direction Is addressed at the input of said increment / decrement circuit to determine.

The alternator further comprises means for generating a third signal on the output terminal resulting from said second signal and comprising said information indicative of the excited state of the alternator.

Means for generating a third signal comprises means for converting the second signal into an output current.

The means for generating the third signal further comprises means for converting the output current into a reverse output current and a selector capable of selectively operating the output current converting means.

The output current converting means comprises a current mirror circuit.

* Circuitry to transmit information indicating the excitation state of an alternator is made monolithic.

The circuitry that carries information indicating the excitation state of the alternator is made monolithic with the regulator circuit.

According to a second aspect of the present invention there is provided a regulator circuit for monitoring a current flowing in an excitation winding of an alternator, wherein the regulator circuit is controlled to be in an on mode or an off mode, and is configured to be connected in series with an excitation winding. And a unidirectional conducting freewheel component connected to a terminal of the excitation winding, and a circuit for transmitting on the output information indicative of the excitation state of the alternator, wherein the circuit for conveying information indicative of the excitation state of the alternator is

Means for generating a first signal proportional to the current flowing in the control switch while the control switch is in the on state,

Means for generating a second signal, while generating a second signal based on the first signal while the control switch is in the on state, while the control switch is turned off while the control switch is in the off state Means for generating a second signal by storing the first signal that has existed before.

Finally, the present invention according to the third aspect provides a circuit for transmitting on the output information indicative of the excitation state of an alternator, which communicates with a regulator circuit and communicates the current flowing in the excitation winding of the alternator. Monitors and is controlled to be in on or off mode and includes a switch in series with the excitation winding and a unidirectional conductive freewheel component connected to the terminals of the excitation winding,

Means for generating a first signal proportional to the current flowing in the control switch by engaging the control switch while the control switch is in the on state;

Means for generating a second signal, which is sensitive to the on or off state of the control switch, while the control switch is in the on state, can generate a second signal based on the first signal, the control switch in the off state While at, the means for generating a second signal by storing the first signal present before the control switch is turned off.

The present invention relates to an alternator or alternator / starter of a motor vehicle, and more particularly to an apparatus adapted to generate a signal indicative of an excitation current flowing in the rotor of such a rotating machine.

Other aspects, objects, and advantages of the invention are apparent from the following detailed description of the preferred embodiments of the invention, given by way of non-limiting examples and given on the basis of the accompanying drawings.

1 shows a circuit according to the invention,

FIG. 2 is a diagram showing two voltages related to the circuit of FIG. 1, a current flowing through an excitation control switch, and a profile of an excitation control signal.

With reference to FIG. 1, in the part on the left side of the figure, and in a general manner as such, the winding FD constituting the excitation or rotor winding of the alternator or alternator / starter of the motor vehicle, and preferably In MOS technology it includes a power transistor (Tex) connected in series with the winding (FD) between the output voltage (Ualt) and the ground of the alternator. The freewheel diode is mounted antiparallel to the winding FD.

The current flowing through the transistor Tex is represented by Iex, and the current actually flowing through the winding FD is represented by Iexc. These two currents are represented by solid and dashed lines in FIG. 2, respectively.

Also, in general, the gate of transistor Tex receives an excitation control signal Cex whose profile consists of a pulse width modulated signal, which is also shown in FIG.

In FIG. 2, it can be seen that the current Iexc has a very small ripple component due to the smoothing effect of the inductance of the winding FD. In this part, the current Iex is chopped by the transistor Tex, and the currents Iex and Iexc are added only when Tex is closed.

The device according to the invention provides a signal indicative of the level of the excitation current Iexc and the circuit 10 for measuring the current in the three main parts, i.e., the transistor Tex, the circuit 20 for storing the measured value, and And an output circuit 30 that can deliver.

First, the circuit 10 includes a transistor Tex and a transistor Tm mounted as a current mirror. This transistor Tm has a source connected to the voltage Ualt and a gate connected to the gate of Tex.

Thus, transistor Tm can replicate current Iex flowing between the source and drain of Tex as current Im and using a predetermined fixed attenuation coefficient. For example, this coefficient is 1/1000.

Preferably, in order to ensure a good ratio between the currents Iex and Im, the transistor Tm is produced using the same basic cell as the power transistor Tex. In the example selected herein, it is sufficient to generate a Tm equal to the number of 1/1000 of the component cells of the transistor Tm using multiple component cells.

For proportional replication of the current Tex of Tm, the three terminals of each transistor need to be at the same potential respectively. It can be seen that the source and the gate of the transistor are connected to each other. Regarding the drain potential, it can be seen from FIG. 1 that the drains are connected to each other by the inverting and non-inverting inputs of the operational amplifier A1 having the intrinsic characteristic that the two inputs are maintained at the same potential. Thus, the condition of the operational amplifier is satisfied.

The drain of Tm is further connected to the base addressed by the emitter of the PNP bipolar transistor T1 and the output of Al. The measuring circuit 10 further includes a resistor R1 connected between the collector of T1 and the ground, a resistor R2 mounted in series between the drain of Tex and the ground, and a clipping zener diode DZ1. The collector of T1 is also connected to the non-inverting input of operational amplifier A2 which by definition does not induce current.

The current I1 on the collector of T1 becomes equal to the current Im within the drain current of T1, which is negligible here.

It can be seen that between the terminals of R1 this current produces a voltage U1 equal to R1 × I1, which is in the form of a signal with the same waveform and proportional level as the current Iex in Tex. .

On their common terminal, resistor R2 and clipping diode DZ1 (the reverse breakdown voltage is preferably selected equal to 5 volts) generate a logic signal EN representing the open or closed state of transistor Tex. . Thus, when Tex is closed, current flows in R2 and DZ1, signal EN is at logic level "1", however, when Tex is open, reverse current flows in SZ1 and R2, and logic signal EN is grounded. A small level below zero volts of, including a logic level "0" is typically at a level corresponding to a junction voltage of DZ1 of -0.8 volts.

First, the storage circuit 20 includes an increase / decrease circuit CD, the parallel output of which is connected to the parallel input of the digital / analogue converter CNA. The circuit 20 also includes an input to a clock signal CK (or, as a variable, an internal clock) that sets the increment and decrement timing executed by the circuit DC. The operational amplifier A2 mounted as a comparator receives the voltage U1 on the non-inverting input (described above) at the output of the converter CNA, and receives the voltage U2 on the inverting input. The purpose of the comparator A2 is to generate a logic signal Up / Dn with respect to the increase / decrease direction applied to the corresponding input of the increase / decrease CD.

The storage circuit 20 operates as follows.

When Tex is open, the signal EN is at logic level "0", as a result, the increase / decrease CD is frozen, and thus the voltage U2 is kept at a constant value.

If Tex is currently closed, signal EN is at logic level "1" to activate the increase / decrease of CD, and there are two possibilities.

If U2 < U1, then the output of A2 is at a logic level " 1 " corresponding to an increase in the circuit CD, and the value of U2 increases and approaches U1.

However, if U2> U1, then the output of A2 is at logic level " 0 " which causes a reduction in circuit CD, and the value of U2 decreases and approaches U1.

As soon as Tex is closed, the circuit CNA delivers a voltage U2 that is maintained at abat as close to U1 as possible by feedback. However, as soon as Tex is opened, the increase / decrease CD is stopped so that U2 has the final value obtained before Tex is opened, as long as Tex is opened.

The variation profile of voltage U2 (in solid line) is shown in FIG. 2. Thus, by latching on the peak value of U1 (shown in dashed lines), it can be seen that the voltage U2 is significantly proportional to the current flowing through the winding FD substantially.

It can be seen here that voltage U2 can be used directly as the output of the circuit of the invention. However, in the case of an environment exposed to electromagnetic interference, such a signal may be distorted by such interference or by a sudden change in ground potential that may occur in an automobile.

In addition, the ohmic value of the resistor R1 can be changed by a considerable amount, especially when made by the monolithic technique.

Thus, the apparatus of the present invention preferably includes an output circuit 30. This circuit comprises a current generator built around operational amplifier A3, an NPN bipolar transistor T2 and a resistor R3. On the non-inverting input, amplifier A3 receives the voltage U2 generated by the storage circuit 20, the inverting input of which is connected to the emitter of T2. In some cases, the output of A3 is connected to the base of T2. Resistor R3 is mounted between the emitter of T2 and ground.

The circuit 30 also includes a current mirror circuit and a selector Com built around the MOS transistors T3 and T4, the PNP bipolar transistor T5, the resistors R4 and R5 and the bipolar diode D1. do. More specifically, the moving contact of the selector Com is connected to the collector of T2, one of which is connected to the base of T5 as well as to the cathode of D1. The anode of D1 is connected to the gate and the drain of T3, the source of which is connected to the voltage Ualt through the resistor R4. On the other side of the current mirror, resistor R5 has a source connected to voltage Ualt through resistor R5, the gate is connected to the gate of T4, and the drain is connected to the emitter of T5. The other fixed contact of the selector Com is connected to the collector of T5 as well as to the output terminal Sim of the device.

The output circuit 30 operates as follows. First, in the collector of T2, the current generator circuits A3, T2, R3 generate a current Is1 proportional to the voltage U2. Also, if an ohmic value equal to the ohmic value of R1 is selected for R3, current Is1 is substantially equal to current Im during the step of closing Tex.

When the circuit Com has a moving contact at the position indicated by the solid line, the current mirrors T3, T4, T5, D1, R4, R5 are proportional to or equal to Is1 on the collector of T5 and thus on the output terminal Sim. It operates to generate the output current Is2.

It should be noted that the junction voltage of diode D1 located near T3 allows for matching biasing at T3 and T4 and, given T4, will in part represent the emitter / base junction voltage of T5.

It can also be seen that the resistors R4 and R5 are balanced resistors that allow a good proportionality or uniformity between the currents Is1 and Is2.

Conversely, in the case where the selector Com occupies a position indicated by a dot, this is a current Is2 applied directly as an input current on the output terminal Sim.

For this reason, by providing an "output current" output mode and an "input current" output mode, the selector Com is quite compatible for interfacing the existing engine monitoring device with the device of the present invention.

As shown, the apparatus described above has good characteristics in terms of thermal compensation. In particular, the currents Is1 and Is2 generated as outputs have a significant proportion (or uniformity) with the current I1 which is proportional to the current in the transistor Tex.

More specifically, during the phase where Tex is on, due to design the following applies.

U1 = U2 = U3

The following also applies.

U1 = R1I1 and

U3 = R3Is1

If the ratio of R1 / R3 is constant, the proportionality between I1 and I3 is guaranteed.

Also, if the case where R1 = R3 is selected, the following applies.

Is1 = I1

Here, with respect to the proportionality between Im (substantially the same as I1) and Iex, it is possible for the transistors Tex, TM to be biased in the same way and made using the same component cells on a common semiconductor substrate.

Finally, by using matching biased transistors T3 and T4 and resistors with proportional or matching resistance, proportionality or uniformity between Is1 and Is2 is ensured.

As mentioned above, the apparatus described above is preferably manufactured in the form of a monolithic circuit, preferably on the excitation regulator circuit of the alternator or alternator / starter (in particular comprising transistors Tex and diodes DL). Is manufactured. In this case, transistors which satisfy the function of the current mirrors (ie Tex and Tm on the one hand and T3 and T4 on the other) are preferably manufactured on the basis of the same component cells. In addition, the resistors R1 and R3 on the one hand and the resistors R4 and R5 on the other hand are preferably manufactured to be exposed to the same thermal conditions.

As described above, the circuit of FIG. 1 may transmit a signal indicative of an exciting current to the engine monitoring device in the form of a current. In this case, the engine monitoring device is provided with an analog / digital conversion device capable of deriving from this current a digital value that can be used for the processing operation to be executed.

As a variable, the circuit of FIG. 1 may comprise such an analog-to-digital conversion circuit under the terminal sim, in which case the information is in accordance with standard digital forms or protocols such as "bit sync" or "LIN". It is transmitted in digital form to the monitoring device.

Claims (17)

In the automotive alternator, A regulator circuit comprising an excitation winding (FD) and a switch (Tex) which is a circuit for regulating the current flowing in the excitation winding (FD) of the alternator and is in series with the excitation winding and controlled to be in an on mode or an off mode; A freewheel component of unidirectional conduction connected to the terminals of the windings and circuits (10, 20, 30) for conveying information (Is1, Is2) indicative of the excited state (Iexc) of the alternator on an output (Sim), The circuit for transmitting information indicating the exciting state of the alternator is Means 10 for generating a first signal U1 proportional to the current Iex flowing in the control switch while the control switch is in the on state, Means 20 for generating a second signal U2, while the control switch is in the on state, it is possible to generate the second signal based on the first signal U1, the control switch in the off state While being at, said means for generating said second signal (U2) by storing said first signal (U1) present before said control switch is turned off. The method of claim 1, The means for generating the first signal (10) includes an alternator for automobiles comprising a current mirror circuit (Tex, Tm) comprising a first semiconductor switch (Tex) consisting of the control switch and a second semiconductor switch (TM). . The method of claim 2, The first and second semiconductor switches are automotive alternators including first and second transistors (Tex, Tm) consisting of the same component cells. The method of claim 3, wherein The second transistor (Tm) comprises a plurality of component cells equal to a small fraction of the number of cells of the components of the first transistor (Tex). The method of claim 2, The means for generating the first signal (10) further comprises a means (R1) for converting the current (Im) flowing in the second semiconductor switch into a voltage constituting the first signal (U1) . The method of claim 1, The means 20 for generating the second signal includes means (A2, CD) capable of generating digital information representing the first signal while the control switch (Tex) is in the on state, and the control switch ( Means (R2, DZ1, CD) for selectively storing said digital value from the moment Tex) is turned off. The method of claim 6, The means for selectively storing the digital value comprises an increase / decrease circuit (CD) for receiving on the input a turn off signal (EN) which is set on the basis of the current in the control switch (Tex) which becomes zero. . The method of claim 6, The means for generating the second signal comprises: a comparator for receiving the first signal U1 on a first input and receiving an analog signal U2 obtained by conversion of the digital information (CNA) on a second input ( A2), wherein the output Up / Dn is addressed to an input of the increase / decrease circuit CD to determine the increase / decrease direction. The method of claim 1, A vehicle 30 further comprising means 30 for generating on said output terminal Sim a third signal Is1, Is2, which is generated from said second signal U2 and comprises said information indicative of the excited state of said alternator; AC alternator. The method of claim 9, The means (30) for generating said third signal comprises means (A3, T2, R3) for converting said second signal (U2) into an output current (Is1). The method of claim 10, The means 30 for generating the third signal comprises means (T3, T4, T5, D1, R3, R4) for converting the output current into reverse output current Is2, and output current converting means Is1 or Is2. Automotive alternator further comprises a selector (Com) that can selectively operate. The method of claim 11, The output current converting means (T3, T4, T5, D1, R3, R4) comprises a current mirror circuit. The method of claim 1, Circuit for transmitting information indicating the excited state of the alternator (10, 20, 30) is an automotive alternator manufactured monolithically. The method of claim 13, The circuit (10, 20, 30) for transmitting information indicating the excited state of the alternator is a motor alternator for monolithic manufacturing with the regulator circuit (Tex, DL). The method of claim 2, The current measuring circuit (10) comprises means (A1, T1) for holding the three terminals of the excitation (Tex) and measurement (TM) transistors, respectively, at a matching potential. In the regulator circuit, An excitation circuit (FD) for monitoring the current flowing in the excitation winding (FD) of the alternator, the switch (Tex) controlled in an on or off mode and connected in series with the excitation winding, and the excitation winding A freewheel component of one-way conduction connected to a terminal of the circuit, and circuits 10, 20, and 30 for transmitting the information Is1, Is2 representing the excited state Isex of the alternator on an output Sim; , The circuits 10 20 and 30 for transmitting information indicating the excited state of the alternator are Means (10) for generating a first signal (U1) proportional to the current (Iex) flowing in the control switch while the control switch (Tex) is in the on state, Means 20 for generating a second signal U2, while the control switch Tex is in the on state, it is possible to generate the second signal U2 based on the first signal U1 And said means (20) for generating said second signal (U2) by storing said first signal (U1) present before said control switch (Tex) is turned off. In a monolithic circuit, An output for transmitting on the output information indicative of the excitation state (Iex) of the alternator, said circuit being interconnected with regulator circuits (Tex, DL) adapted to monitor the current (Iexc) flowing in the excitation winding of the alternator; A switch (Tex) which is adapted to be in communication and is in an on mode and an off mode and is in series with the exciting winding, and a freewheel component of unidirectional conduction (DL) connected to the terminal of the exciting winding, Means (10) for generating a first signal (U1) in combination with the control switch and also while the control switch is in the on mode, proportional to the current Iex flowing in the control switch, Means 20 for generating a second signal U2, which is sensitive to the on or off state of the control switch, while the control switch is in the on state, based on the first signal U1; The second signal U2 can be generated, and while the control switch is in the off state, the second signal U2 can be generated by storing the first signal U1 that exists before the control switch is turned off. Monolithic circuit comprising means for generating (20).